As this kind of a pointing device, there is provided one which includes an operating body in which one end operably protrudes from an opening of a cover portion of a case body and which is movable depending on the above-mentioned operation toward a horizontal direction from an origin position that is a central position of the opening; first and second moving bodies having first and second elongated holes extending in the Y and X directions, into which the other end of the operating body is inserted and which are movable in the X and Y directions depending on movement of the operating body; first and second signal output units which output first and second signals depending on movement of the first and second moving bodies; and an origin returning mechanism for returning the operating body to the origin position.
The origin returning mechanism is configured to include first and second coil springs which are accommodated along the X and Y directions in first and second accommodation portions provided at one end in a length direction of the first and second moving bodies; and a pair of protruding-like first and second restraining portions arranged at spaces along the X and Y directions at positions capable of coming into contact with both ends of the first and second coil springs of the case body (refer to Japanese Unexamined Patent Application Publication No. 2001-255995).
In other words, when the operating body is movement-operated and the first and second moving bodies are moved in the X and Y directions, the first and second coil springs are compressed between one wall surface in the length direction of the first and second accommodation portions and the other of the first and second restraining portions. After that, when the operating body is released, the first and second moving bodies are returned to move in the Y and X directions by biasing force of the first and second coil springs, thereby returning the operating body to the origin position.
In this regard, however, the origin returning mechanism uses two coil springs and therefore there is a problem in that the operating body cannot be returned highly precisely to the origin position due to variation in spring force of these coil springs. More particularly, when the origin returning mechanism is used for a long time, there is a possibility of increasing the variation in the spring force of the coil spring, and therefore the problem becomes remarkable.
Furthermore, even where the operating body is positioned at the origin position, there is a case that the first and second moving bodies further move in the Y and X directions due to inertia force of returning movement. Such movement which exceeds the origin position causes false operation in the case where sensitive operation is required. Also in this regard, the operating body cannot be highly precisely returned to the origin position.
The exemplary embodiments disclosed herein have been devised in view of the above-described problems, and it is a feature of certain exemplary embodiments to provide an origin returning mechanism of a pointing device and a pointing device using the same, which can perform highly precise returning operation of an operating body.
To solve the above problems, according to certain exemplary embodiments, there is provided an origin returning mechanism of a pointing device having an operating body in which one end operably protrudes from an opening of a cover portion of a case body and which is movable depending on the operation toward a horizontal direction from an origin position that is a central position of the opening, the origin returning mechanism including: a first biasing means for retaining the operating body at the origin position by biasing an outer circumference surface of the first returning assisting plate; a fitting block accommodated movably in and out of the reception hole of the first returning assisting plate; and a second biasing means for biasing the fitting block toward the cover portion of the case body. The fitting block protrudes from the reception hole of the first returning assisting plate to fit into the opening of the case body by being biased with the second biasing means when the operating body is located at the origin position.
It is a feature of certain exemplary embodiments that a surface of the fitting block facing the cover portion and/or a surface of an opening edge of the cover portion of the case body facing the fitting block are/is tapered.
In the case where the opening of the cover portion of the case body is substantially round, the first returning assisting plate is a substantially round-shaped plate-like body; and the first biasing means is a coil spring in which one end in a longitudinal direction is shrunk in diameter as compared with the other end, the one end coming into contact with the outer circumference surface of the first returning assisting plate.
The operating body may be provided with a plate-like portion under the arrangement position of the first returning assisting plate. In this case, the second biasing means is a coil spring in which one end in a longitudinal direction is shrunk in diameter as compared with the other end and is arranged between the fitting block and the plate-like portion in a compressed state.
It is a feature of certain exemplary embodiments that the second returning assisting plate formed in a ring shape is provided at an upper portion of the outer circumference surface of the first returning assisting plate. In this case, one end of the first biasing means comes into contact with a lower portion of the outer circumference surface of the first returning assisting plate and a lower surface of the second returning assisting plate.
According to certain exemplary embodiments, there is provided a pointing device including: an operating body in which one end operably protrudes from an opening of a cover portion of a case body and which is movable depending on the operation toward a horizontal direction from an origin position that is a central position of the opening; first and second moving bodies movable depending on the movement of the operating body in X and Y directions in the case body; and first and second signal output units which output a signal depending on the movement of the first and second moving bodies. The pointing device includes the origin returning mechanism as described above which returns the operating body to the origin position.
The case body includes an upper case having the cover portion, a lower case mounted on the upper case, and a pedestal arranged between the upper and lower cases. On a surface of the pedestal facing the cover portion of the upper case, there is provided a substantially sphere-like convex portion in which a center is located on the plumb line of the origin position and which is convexly curved toward the cover portion. In this case, the surface of the plate-like portion facing the convex portion is a sphere-like concave surface and the plate-like portion is slidable on the convex portion with the movement of the operating body.
In a space between the pedestal and the lower case, a built-in board disposed on a bottom plate of the lower case and first and second moving bodies movable in X and Y directions along on the surface of the built-in board are accommodated. The pedestal is provided with a hole portion in which a center is located on the plumb line of the origin position and the first and second moving bodies are provided with first and second elongated holes extending in the Y and X directions. The other end of the operating body passes through the hole portion of the pedestal to be inserted into the elongated holes provided in the first and second moving bodies.
The first and second signal output units includes: first and second resistance circuits provided on the surface of the built-in board; and first and second contacts attached at longitudinal ends of the first and second moving bodies and slidably connectable to the first and second resistance circuits.
The origin returning mechanism of the pointing device according to certain exemplary embodiments is such that the outer circumference surface of the first returning assisting plate is biased by the first biasing means to retain the operating body at the origin position. That is, it is such that the operating body is returned to the origin position by only the biasing force of the first biasing means and therefore returning operation of the operating body can be highly accurately performed, not suffering from spring force variation caused by a plurality of coil springs as in the conventional example. Furthermore, the fitting block is biased by the second biasing means when the operating body is located at the origin position and therefore the operating body protrudes from the reception hole to fit into the opening of the case body, whereby the operating body can be stopped at the origin position. Therefore, the operating body undergoing the biasing force of the first biasing means will not move beyond the origin position by inertia force of the returning movement. Consequently, in this regard also, the returning operation of the operating body can be highly accurately performed.
Furthermore, in the case where a surface of the fitting block facing the cover portion and/or a surface of an opening edge of the cover portion of the case body facing the fitting block are/is tapered, large force is not required in a starting operation of the operating body for releasing the fitting between the fitting block and the opening of the cover portion of the case body. Consequently, operability of the operating body is increased. Furthermore, in the returning movement, when the fitting block is biased toward the cover portion with the second biasing means in a state where the surface of the fitting block facing the cover portion is sliding on the surface of the opening edge of the cover portion of the case body facing the fitting block; the aforementioned fitting block moves toward the origin position together with the operating body. That is, the biasing force of the second biasing means also contributes as the returning force of the operating body when the operating body is located in the vicinity of the origin position. Therefore, the returning force due to the biasing force of the first biasing means which becomes small in the vicinity of the origin position can be strengthened again and therefore the operating body can be rapidly returned to the origin position.
If the first biasing means is a coil spring in which one end in a longitudinal direction is shrunk in diameter as compared with the other end, this one end of the biasing means comes into contact with the outer circumference surface of the first returning assisting plate which is a substantially round plate-like body so as to bias the first returning assisting plate. Therefore, it becomes possible to uniformize the returning force of the operating body and therefore the returning operation of the operating body can be highly accurately performed.
Furthermore, if the second biasing means is a coil spring in which one end in a longitudinal direction is shrunk in diameter as compared with the other end and if the second biasing means is arranged in a compressed state between a plate-like portion provided under the arrangement position of the first returning assisting plate of the operating body and the fitting block, the second biasing means becomes movable with movement of the operating body and therefore the second biasing means is distorted due to the movement of the operating body and it becomes possible to prevent from generating ununiformization of the biasing force with respect to the fitting block.
In the case where one end of the first biasing means comes into contact with a lower portion of the outer circumference surface of the first returning assisting plate and a lower surface of the ring-shaped second returning assisting plate provided on the upper portion of the outer circumference surface of the first returning assisting plate, the second returning assisting plate enables transmission of the biasing force of the first biasing means to the operating body without missing the biasing force. Consequently, there is a merit that the returning operation of the operating body can be highly accurately performed.
The pointing device according to certain exemplary embodiments can exhibit the same effects as in the above-mentioned origin returning mechanism of the pointing device.
Furthermore, in the case where a pedestal of the case body is provided with a substantially sphere-like convex portion in which a center is located on the plumb line of the origin position and which is convexly curved toward the cover portion of the upper case, a surface of the plate-like portion provided on the operating body facing the convex portion is a sphere-like concave surface, and the concave surface is slidable on the convex portion with the movement of the operating body; sliding operation can be performed in the horizontal direction while the operating body is maintained at a predetermined leaning angle. Consequently, operability of the operating body is improved.
If a space between the pedestal and the lower case accommodates a built-in board disposed on the bottom plate of the lower case, first and second moving bodies movable in X and Y directions along on the surface of the built-in board, and the first and second signal output units outputting a signal depending on the movement of the first and second moving bodies are accommodated; the origin returning mechanism of the pointing device may be accommodated in a separate space from the space for the first and second moving bodies and signal output units of the pointing device, whereby preventing the two mechanisms from interfering with each other.